Government demands answers from Orica

The New South Wales government is demanding answers from chemical giant, Orica over two pollution incidents at its Newcastle ammonia plant this month.

Deputy Chief Executive of the Office of Environment and Heritage, Greg Sullivan says the arsenic spill into the Hunter River last week on Friday was considered only a minor incident.

But, he says coming so soon after the recent leak of the toxic chemical, hexavalent chromium, there is now real concern about what is happening at the Orica plant.

"We're concerned there might be systemic issues on that plant," he said.

"As a result the Chief Executive of Orica has been summonsed to a meeting with the head of both the Department of Premier and Cabinet, and the Chief Executive of the Office of Environment and Heritage this morning.

"They'll be delivering the Premier's very clear message that these two incidents in two weeks are not good enough and demanding that Orica improve the operation of that plant."